96-27522. Airworthiness Directives; Learjet Model 31 and 35A Airplanes  

  • [Federal Register Volume 61, Number 209 (Monday, October 28, 1996)]
    [Proposed Rules]
    [Pages 55584-55585]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 96-27522]
    
    
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    Proposed Rules
                                                    Federal Register
    ________________________________________________________________________
    
    This section of the FEDERAL REGISTER contains notices to the public of 
    the proposed issuance of rules and regulations. The purpose of these 
    notices is to give interested persons an opportunity to participate in 
    the rule making prior to the adoption of the final rules.
    
    ========================================================================
    
    
    Federal Register / Vol. 61, No. 209 / Monday, October 28, 1996 / 
    Proposed Rules
    
    [[Page 55584]]
    
    
    
    DEPARTMENT OF TRANSPORTATION
    
    Federal Aviation Administration
    
    14 CFR Part 39
    
    [Docket No. 96-NM-202-AD]
    RIN 2120-AA64
    
    
    Airworthiness Directives; Learjet Model 31 and 35A Airplanes
    
    AGENCY: Federal Aviation Administration, DOT.
    
    ACTION: Notice of proposed rulemaking (NPRM).
    
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    SUMMARY: This document proposes the supersedure of an existing 
    airworthiness directive (AD), applicable to certain Learjet Model 31 
    and 35A airplanes, that currently requires replacement of two segments 
    of 16 American Wire Gauge (AWG) wire with 8 AWG wire at the connector 
    that is connected to the auxiliary cabin heater relay box. That AD was 
    prompted by a report indicating that two segments of the 16 AWG wire in 
    the auxiliary cabin heater, which were spliced during production, do 
    not provide adequate current-carrying capacity. This new proposed 
    action would require the installation of a new replacement wire 
    assembly. The actions specified by the proposed AD are intended to 
    prevent electrical arcing and consequent fire hazard that could result 
    from wiring with inadequate current-carrying capacity.
    
    DATES: Comments must be received by December 9, 1996.
    
    ADDRESSES: Submit comments in triplicate to the Federal Aviation 
    Administration (FAA), Transport Airplane Directorate, ANM-103, 
    Attention: Rules Docket No. 96-NM-202-AD, 1601 Lind Avenue, SW., 
    Renton, Washington 98055-4056. Comments may be inspected at this 
    location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
    Federal holidays.
        The service information referenced in the proposed rule may be 
    obtained from Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-
    2942. This information may be examined at the FAA, Transport Airplane 
    Directorate, 1601 Lind Avenue, SW., Renton, Washington.
    
    FOR FURTHER INFORMATION CONTACT: Dale Bleakney, Aerospace Engineer, 
    Flight Test Branch, ACE-117W, FAA, Wichita Aircraft Certification 
    Office, Small Airplane Directorate, 1801 Airport Road, Room 100, Mid-
    Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4135; fax 
    (316) 946-4407.
    
    SUPPLEMENTARY INFORMATION:
    
    Comments Invited
    
        Interested persons are invited to participate in the making of the 
    proposed rule by submitting such written data, views, or arguments as 
    they may desire. Communications shall identify the Rules Docket number 
    and be submitted in triplicate to the address specified above. All 
    communications received on or before the closing date for comments, 
    specified above, will be considered before taking action on the 
    proposed rule. The proposals contained in this notice may be changed in 
    light of the comments received.
        Comments are specifically invited on the overall regulatory, 
    economic, environmental, and energy aspects of the proposed rule. All 
    comments submitted will be available, both before and after the closing 
    date for comments, in the Rules Docket for examination by interested 
    persons. A report summarizing each FAA-public contact concerned with 
    the substance of this proposal will be filed in the Rules Docket.
        Commenters wishing the FAA to acknowledge receipt of their comments 
    submitted in response to this notice must submit a self-addressed, 
    stamped postcard on which the following statement is made: ``Comments 
    to Docket Number 96-NM-202-AD.'' The postcard will be date stamped and 
    returned to the commenter.
    
    Availability of NPRMs
    
        Any person may obtain a copy of this NPRM by submitting a request 
    to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
    Docket No. 96-NM-202-AD, 1601 Lind Avenue, SW., Renton, Washington 
    98055-4056.
    
    Discussion
    
        On May 15, 1996, the FAA issued AD 96-11-07, amendment 39-9632 (61 
    FR 26090, May 24, 1996), applicable to certain Learjet Model 31 and 35A 
    airplanes, to require replacement of two segments of 16 American Wire 
    Gauge (AWG) wire with 8 AWG wire at the connector that is connected to 
    the auxiliary cabin heater relay box. That action was prompted by a 
    report that two segments of the 16 AWG wire in the auxiliary cabin 
    heater that were spliced during production do not provide adequate 
    current-carrying capacity. The requirements of that AD are intended to 
    prevent electrical arcing and consequent fire hazard that could result 
    from wiring with inadequate current-carrying capacity.
    
    Actions Since Issuance of Previous Rule
    
        Since the issuance of that AD, the FAA has been notified that the 
    replacement installation kit specified in Learjet Service Bulletins SB 
    31-21-10 and SB 35-21-24, (which were referenced in AD 96-11-07 as the 
    appropriate sources of service information) contains a socket contact 
    that has an incorrect part number for use in the P190 connector. This 
    incorrect part number prevents the replacement equipment from being 
    installed properly.
        The FAA recently reviewed and approved Revision 1 of Learjet 
    Service Bulletins SB 31-21-10, dated May 17, 1996 (for Model 31 
    airplanes), and SB 35-21-24, dated May 17, 1996 (for Model 35 
    airplanes). These revised service bulletins describe new replacement 
    procedures that include installing a new wire assembly kit that 
    contains the correct socket contact, as well as a precrimped 8 AWG wire 
    (2 ft. in length).
        The FAA finds that accomplishment of the wiring assembly 
    installation using this new replacement installation kit will 
    positively address the unsafe condition identified as electrical arcing 
    and consequent fire hazard, as a result of wiring with inadequate 
    current- carrying capacity.
    
    Explanation of Requirements of Proposed Rule
    
        Since an unsafe condition has been identified that is likely to 
    exist or develop on other products of this same type design, the 
    proposed AD would
    
    [[Page 55585]]
    
    supersede AD 96-11-07. It would require replacement of the two segments 
    of 16 AWG wire with a 8 AWG wire at the P190 connector that is 
    connected to the E33 auxiliary cabin heater relay box. The actions 
    would be required to be accomplished in accordance with Revision 1 of 
    the service bulletins described previously.
        The FAA has been advised that some operators, when attempting to 
    comply with AD 96-11-07, may already have replaced the wiring assembly 
    using the correct part in the P190 connector, which would be mandated 
    by this proposed AD. For those operators, no additional work would be 
    required by this AD.
    
    Cost Impact
    
        There are approximately 52 Learjet Model 31 and 35A airplanes of 
    the affected design in the worldwide fleet. The FAA estimates that 44 
    airplanes of U.S. registry would be affected by this proposed AD.
        The actions that are proposed in this AD action would take 
    approximately 4 work hours per airplane to accomplish, at an average 
    labor rate of $60 per work hour. Required parts would be supplied by 
    the manufacturer at no cost to the operators. Based on these figures, 
    the cost impact on U.S. operators of the proposed requirements of this 
    AD is estimated to be $10,560, or $240 per airplane.
        The cost impact figures discussed above are based on assumptions 
    that no operator has yet accomplished any of the current or proposed 
    requirements of this AD action, and that no operator would accomplish 
    those actions in the future if this AD were not adopted. The FAA has 
    been advised, however, that some operators already have installed 
    equipment that is the equivalent to that which would be required by 
    this AD. Therefore, the future economic cost impact of this proposed 
    rule on U.S. operators is expected to be less than the cost impact 
    figure indicated above.
    
    Regulatory Impact
    
        The regulations proposed herein would not have substantial direct 
    effects on the States, on the relationship between the national 
    government and the States, or on the distribution of power and 
    responsibilities among the various levels of government. Therefore, in 
    accordance with Executive Order 12612, it is determined that this 
    proposal would not have sufficient federalism implications to warrant 
    the preparation of a Federalism Assessment.
        For the reasons discussed above, I certify that this proposed 
    regulation (1) is not a ``significant regulatory action'' under 
    Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
    Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
    and (3) if promulgated, will not have a significant economic impact, 
    positive or negative, on a substantial number of small entities under 
    the criteria of the Regulatory Flexibility Act. A copy of the draft 
    regulatory evaluation prepared for this action is contained in the 
    Rules Docket. A copy of it may be obtained by contacting the Rules 
    Docket at the location provided under the caption ADDRESSES.
    
    List of Subjects in 14 CFR Part 39
    
        Air transportation, Aircraft, Aviation safety, Safety.
    
    The Proposed Amendment
    
        Accordingly, pursuant to the authority delegated to me by the 
    Administrator, the Federal Aviation Administration proposes to amend 
    part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
    follows:
    
    PART 39--AIRWORTHINESS DIRECTIVES
    
        1. The authority citation for part 39 continues to read as follows:
    
        Authority: 49 U.S.C. 106(g), 40113, 44701.
    
    
    Sec. 39.13  [Amended]
    
        2. Section 39.13 is amended by removing amendment 39-9632 (61 FR 
    26090, May 24, 1996), and by adding a new airworthiness directive (AD), 
    to read as follows:
    
    Learjet, Inc.: Docket 96-NM-202-AD. Supersedes AD 96-11-07, 
    Amendment 39-9632.
    
        Applicability: Model 31 airplanes having serial numbers 31-002 
    through 31-029 inclusive, and Model 35A airplanes having serial 
    numbers 35-647 through 35-670 inclusive; certificated in any 
    category.
    
        Note 1: This AD applies to each airplane identified in the 
    preceding applicability provision, regardless of whether it has been 
    otherwise modified, altered, or repaired in the area subject to the 
    requirements of this AD. For airplanes that have been modified, 
    altered, or repaired so that the performance of the requirements of 
    this AD is affected, the owner/operator must request approval for an 
    alternative method of compliance in accordance with paragraph (b) of 
    this AD. The request should include an assessment of the effect of 
    the modification, alteration, or repair on the unsafe condition 
    addressed by this AD; and, if the unsafe condition has not been 
    eliminated, the request should include specific proposed actions to 
    address it.
    
        Compliance: Required as indicated, unless accomplished 
    previously.
        To prevent electrical arcing and consequent fire hazard, 
    accomplish the following:
        (a) Within 6 months after the effective date of this AD, replace 
    two segments of 16 American Wire Gauge (AWG) wire with 8 AWG wire at 
    the P190 connector that is connected to the E33 auxiliary cabin 
    heater relay box, in accordance with Learjet Service Bulletin SB 31-
    21-10, Revision 1, dated May 17, 1996 (for Model 31 airplanes), or 
    Learjet Service Bulletin SB 35-21-24, Revision 1, dated May 17, 1996 
    (for Model 35A airplanes), as applicable.
    
        Note 2: Accomplishment of the replacement in accordance with the 
    procedures specified in Learjet Service Bulletin SB 31-21-10 or SB 
    35-21-24 (original issue), both dated August 11, 1995, but using 
    equipment that is identical or equivalent to that of the applicable 
    kit specified in Revision 1 of those service bulletins, is 
    considered to be acceptable for compliance with the requirements of 
    paragraph (a) of this AD.
    
        (b) An alternative method of compliance or adjustment of the 
    compliance time that provides an acceptable level of safety may be 
    used if approved by the Manager, Wichita Aircraft Certification 
    Office (ACO), FAA, Small Airplane Directorate. Operators shall 
    submit their requests through an appropriate FAA Principal 
    Maintenance Inspector, who may add comments and then send it to the 
    Manager, Wichita ACO.
    
        Note 3: Information concerning the existence of approved 
    alternative methods of compliance with this AD, if any, may be 
    obtained from the Wichita ACO.
    
        (c) Special flight permits may be issued in accordance with 
    sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
    CFR 21.197 and 21.199) to operate the airplane to a location where 
    the requirements of this AD can be accomplished.
    
        Issued in Renton, Washington, on October 21, 1996.
    James V. Devany,
    Acting Manager, Transport Airplane Directorate, Aircraft Certification 
    Service.
    [FR Doc. 96-27522 Filed 10-25-96; 8:45 am]
    BILLING CODE 4910-13-U
    
    
    

Document Information

Published:
10/28/1996
Department:
Federal Aviation Administration
Entry Type:
Proposed Rule
Action:
Notice of proposed rulemaking (NPRM).
Document Number:
96-27522
Dates:
Comments must be received by December 9, 1996.
Pages:
55584-55585 (2 pages)
Docket Numbers:
Docket No. 96-NM-202-AD
RINs:
2120-AA64: Airworthiness Directives
RIN Links:
https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives
PDF File:
96-27522.pdf
CFR: (1)
14 CFR 39.13